fix(parser): Allow multiple instances for all commands except TakeScreenshot

Refined the single-instance command logic in CommandParser.kt's
`processTextInternal` method.

Previously, several command types (e.g., home, back, model changes) were
treated as single-instance per parsing pass. This change modifies the logic
so that only `CommandTypeEnum.TAKE_SCREENSHOT` is subject to this
single-instance filtering.

All other command types can now be parsed multiple times if they appear
sequentially in the input string, allowing for sequences like
"scroll down scroll down" or "home home" to be correctly processed into
multiple distinct commands.

Author: google-labs-jules[bot]

app/src/main/kotlin/com/google/ai/sample/util/CommandParser.kt

@@ -254,13 +254,7 @@ object CommandParser {
                 var canAdd = true
                 // Use commandTypeFromMatch directly here
                 val isSingleInstanceType = when (commandTypeFromMatch) {
-                    CommandTypeEnum.TAKE_SCREENSHOT,
-                    CommandTypeEnum.PRESS_HOME,
-                    CommandTypeEnum.PRESS_BACK,
-                    CommandTypeEnum.SHOW_RECENT_APPS,
-                    CommandTypeEnum.USE_HIGH_REASONING_MODEL,
-                    CommandTypeEnum.USE_LOW_REASONING_MODEL,
-                    CommandTypeEnum.PRESS_ENTER_KEY -> true
+                    CommandTypeEnum.TAKE_SCREENSHOT -> true // Only TakeScreenshot is single-instance
                     else -> false
                 }
                 if (isSingleInstanceType) {